On the return trip, Los Angeles' infamously snarled traffic often stretches their afternoon commute to three hours. Since Paul joined in 2001, he has spent roughly 1½ years aboard the vanpool and traveled far enough to complete a round trip to the moon. Americans living in more sparsely populated areas are affected every time they head to cities for ball games, business, shopping or air travel. In many fast-growing metro areas, transportation officials are trying to avoid becoming the next L.A., Houston or Atlanta — places struggling to undo previous decisions that led to mind-numbing, time-wasting, fuel-burning traffic jams. Faced with traffic congestion so notorious that it has become a cultural touchstone in movies and comedy repertoires, L.A.